I hope you are ready for some travelling because they are at opposite sides of France...
One is right on the Atlantic ocean coast in Western France the other is on the Switzerland boarder on the East side.
570 miles separate them on the motorway (485 miles via small roads)
Alternatively, you can fly from La Rochelle (80 miles from St Jean de Monts) or Nantes (40 miles away) to Geneva (2 miles from St Julien)
Both places are gorgeous, one because it is on the ocean coast, the other because it is near the Alps close to the mountains and lakes...
Have a nice time whatever you decide to do, France is a beautiful place and I hope you will meet decent French people
I'm French, born near Geneva :-)